Aircraft: EMB ERJ 170/175 ER/LR
Phase of flight: Parked
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Weight And Balance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown

This was a maintenance reposition flight from ZZZ to ZZZ1. I was flying as the PIC with a Captain in the right seat. Pushing back from the gate; we had a zero fuel weight (ZFW) of 52;000 lbs. The gross weight on the performance was off by over 4;000 lbs from the data received; and we were out of balance. The aircraft had no passengers; no flight attendants; no baggage; just 14;700 lbs of fuel and two pilots and all galley carts. We called the Dispatcher to inform her that we were out of balance. She told me on the phone that she was [gone] the previous week when we were transitioning to 5 zone weight and balance and she didn't know what was going on; and literally just handed me off to the pilot on duty to figure out. This was totally unacceptable. She is the dispatcher of record; has equal legal responsibility for the planning of this flight and upon being informed that we're out of balance and had our ZFW change by thousands of pounds in a few minutes time; she just hands me off to an unrecorded phone line with the pilot on duty?! My head is still spinning. At the gate; our ZFW was 52;000 lbs. Now we are being told to put numbers in the box for ballast but I have no idea what it means 1.0 2.0 3.0 etc; what does that correspond to? We are not actually moving any ballast anywhere etc. The pilot on duty and some other manager on with him; and myself went back and forth for a good amount of time trying to figure out what the accurate zero fuel weight was; what an accurate gross take off weight was; and my main concern; if our stab trim; and V speeds were accurate and safe. I want to reiterate; this was a total and complete debacle. There was so much confusion on the phone as to how we got these numbers from computer and what they meant; and if they were accurate. I had to ask the pilot on duty and manager point blank on the phone; are you telling me these numbers are accurate; and safe for us to depart; before I would continue this flight any further. This 5 zone weight and balance makes no sense how we could be out of balance with only fuel on board. It does not seem like this 5 zone system was well thought out; or that ferry / reposition flights were accounted for. How this got approved by the FAA is beyond me. Additionally; our FOM states that 'the amount to be considered unusable shall be noted on the dispatch release and be considered as unusable by the flight crew'; no such comment on this release is present. If were using fuel for ballast for CG limits which is totally news to me seeing as we never had a problem with CG on 3 zone weight and balance; then the PIC must be notified because if that fuel is used; an in flight emergency would have to be declared because the aircraft would no longer be within CG limits. Captain reported that dispatch was unable to supply the correct weight and balance information for a scheduled maintenance reposition flight.